Protecting the world’s oceans is a monumental task. And today, with overfishing, pollution, and other human activities causing increasingly catastrophic losses in ocean biodiversity, it has become a vitally important and pressing endeavor. Dissipating the threats to ocean life requires finding a functional balance between the utilization of ocean resources and the development of conservation efforts, which is supported in large part by scientific research.

Marine Sanctuaries

One of the most important aspects of ocean conservation is protecting sensitive areas. In 1972 the U.S. Congress established the Marine Protection, Research, and Sanctuaries Act to regulate the dumping into the ocean of materials that are potentially dangerous to humans and to the marine environment. The act also enabled the establishment of the National Marine Sanctuary System, recognizing that the nation’s coastal waters and lakes are of ecological, scientific, historical, and educational significance.

Sanctuaries fill a crucial role in facilitating marine research, enabling biologists to observe and characterize ocean life and ecosystems. At the Monterey Bay Marine Sanctuary off the coast of California, for example, scientists studying kelp forests have found that these areas provide habitat for certain species of crustaceans, sea urchins, and fish. The loss of kelp from overharvesting leads to decreases in these species that in turn can affect populations of other marine animals, including sea otters, which feed on urchins within kelp forests. Alternatively, intact kelp forests can be affected by shifts in animal populations. For example, decreases in otter populations lead to explosions in urchin populations. This can result in “urchin barren,” in which urchins overgraze on kelp, eating them out of their rock anchors and thereby causing a decrease in kelp-forest biomass and biodiversity.

Human Activities and Ocean Life

Similar to the discoveries of kelp ecosystems, scientists working beyond the boundaries of marine sanctuaries have made numerous discoveries concerning the severe impacts that human activities can have on the well being of ocean life and habitat. Today, one of the most urgent threats to marine life that scientists are working to assess comprehensively is overfishing.

Stocks of highly sought-after fishes in the world’s oceans have sustained staggering declines in recent decades. The Atlantic cod was overfished to the point that, despite an indefinite moratorium in place since 1992, stocks have failed to recover, and they are unlikely to rebound anytime soon. The moratorium was truly too little too late. Indeed, recent studies have indicated that a moratorium on cod fishing alone may not save the species.

Over the course of the last couple of decades, there has occurred a dramatic shift in the food web in the Atlantic Ocean. The loss of large amounts of biomass from overfishing, as well as pollution and global warming, are believed to have caused a severe deficit in energy available to large fish and medium-sized groundfish such as cod. But while cod are starving to death, populations of small pelagic fish such as herring and sprat have experienced tremendous growth. In addition, the dynamics of the ecosystem’s communities of zooplankton and phytoplankton have been altered, presumably due to global warming and increasing water temperature. These tiny creatures form the base of the ocean food web and therefore changes in their communities affect all fish in the ecosystem.

Another disturbance of ocean habitat is pollution, which can occur in various forms, including contaminated runoff, oil spills, and trash. Trash in the ocean is pulled into giant eddies of water, which accumulate plastics and other wastes into floating garbage patches. Take, for instance, the Pacific Gyre, otherwise known as the Great Pacific Garbage Patch, located about 1,000 miles north of Hawaii. It isn’t clear exactly how large the mess is, though some estimates indicate that it encompasses an area approximately two times the size of Texas.

The plastics contained within the patch are exceptionally dangerous to marine life. Photodegradation of plastic materials produces chemicals that are taken up by filter feeders, and in this way toxic substances from the gyre enter the ocean food chain. Furthermore, some animals, including birds, attempt to eat the plastics. A number of Laysan albatross chicks have died as a result of their parents feeding them inedible plastic “foods”; the birds hunt by sight and normally eat floating fish eggs and squid. Plastic floats, and to these birds, it looks like food.

The garbage patch in the Pacific needs to be removed, but because it is so massive, exactly how to go about removing it forms the basis of ongoing explorations to and investigations of the site. On the upside, there is significant value in recycling the plastics accumulated within the gyre.

The Future of Conservation

As we come to understand more about the complexities of the ocean and its inhabitants, marine conservation programs will become increasingly effective. While projects such as the Census of Marine Life continue to break new ground in our understanding of ocean animals, conservation programs are working to synthesize this information with what is known about the anthropogenic factors implicated in the decline of marine habitat and species. These efforts will facilitate the implementation of measures to protect the ocean from the side effects of human activity.